Add /spoiler and /unspoiler

src/backend/html_markdown.py

@@ -138,6 +138,13 @@ class HTMLProcessor:
         re.MULTILINE,
     )
 
+    spoiler_regex = re.compile(
+        r"(<span[^>]+data-mx-spoiler[^>]*>)"
+        r"(.*?)"
+        r"(</?span>)",
+        re.MULTILINE,
+    )
+
     extra_newlines_regex = re.compile(r"\n(\n*)")
 
 
@@ -224,6 +231,7 @@ class HTMLProcessor:
         # Client-side modifications
 
         html = self.quote_regex.sub(r'\1<span class="quote">\2</span>\3', html)
+        html = self.spoiler_regex.sub(r'\1<font color="#00000000">\2</font>\3', html)
 
         if not inline:
             return html
@@ -250,11 +258,11 @@ class HTMLProcessor:
             "font": {"color"},
             "a":    {"href", "class", "data-mention"},
             "code": {"class"},
+            "span": {"data-mx-spoiler", "data-mx-color"},
         }
         attributes = {**inlines_attributes, **{
             "ol":   {"start"},
             "hr":   {"width"},
-            "span": {"data-mx-color"},
             "img":  {
                 "data-mx-emote", "src", "alt", "title", "width", "height",
             },

src/backend/matrix_client.py

@@ -183,6 +183,8 @@ class MatrixClient(nio.AsyncClient):
         self.cmd_handler_map = {
             "me ":        MatrixClient.handle_cmd_emote,
             "react ":     MatrixClient.handle_cmd_react,
+            "spoiler ":   MatrixClient.handle_cmd_spoiler,
+            "unspoiler":  MatrixClient.handle_cmd_unspoiler,
         }
 
         try:
@@ -655,6 +657,8 @@ class MatrixClient(nio.AsyncClient):
         text:                  str,
         display_name_mentions: Optional[Dict[str, str]] = None,  # {id: name}
         reply_to_event_id:     Optional[str]            = None,
+        override_to_html:      Optional[str]            = None,
+        override_echo_body:    Optional[str]            = None,
         emote:                 bool                     = False,
     ) -> None:
         """Send a markdown `m.text` or `m.emote` message ."""
@@ -676,6 +680,12 @@ class MatrixClient(nio.AsyncClient):
             to_html    = from_md(text, outgoing=True)
             echo_body  = from_md(text)
 
+        # override_echo_body will not be effective if it is a reply.
+        # echo_body is only shown before the event is received back from the
+        # server, so this is fine if not ideal
+        to_html   = override_to_html   or to_html
+        echo_body = override_echo_body or echo_body
+
         if to_html not in (html.escape(text), f"<p>{html.escape(text)}</p>"):
             content["format"]         = "org.matrix.custom.html"
             content["formatted_body"] = to_html
@@ -762,6 +772,56 @@ class MatrixClient(nio.AsyncClient):
             await self.send_reaction(room_id, reaction, reply_to_event_id)
 
 
+    async def handle_cmd_spoiler(
+        self,
+        room_id:                str,
+        text:                   str,
+        display_name_mentions:  Optional[Dict[str, str]]  = None,  # {id: name}
+        reply_to_event_id:      Optional[str]             = None,
+    ) -> None:
+
+        from_md = partial(
+            HTML.from_markdown, display_name_mentions=display_name_mentions,
+        )
+
+        to_html    = from_md(text, outgoing=True)
+        echo_body  = from_md(text)
+
+        to_html    = f"<span data-mx-spoiler>{to_html}</span>"
+        echo_body  = f"<span data-mx-spoiler>{echo_body}</span>"
+
+
+        await self._send_text(
+            room_id,
+            text,
+            display_name_mentions,
+            reply_to_event_id,
+            override_to_html = to_html,
+            override_echo_body = echo_body,
+        )
+
+
+    async def handle_cmd_unspoiler(
+        self,
+        room_id:                str,
+        text:                   str,
+        display_name_mentions:  Optional[Dict[str, str]]  = None,  # {id: name}
+        reply_to_event_id:      Optional[str]             = None,
+    ) -> None:
+        if reply_to_event_id is None or reply_to_event_id == '':
+            await self.send_fake_notice(room_id, "Please reply to a message with /unspoiler to unspoiler it 🙃")
+        else:
+            spoiler_event: Event = \
+                self.models[self.user_id, room_id, "events"][reply_to_event_id]
+
+            # get formatted_body, fallback to body,
+            spoiler = getattr(spoiler_event.source, "formatted_body", None) or \
+                      getattr(spoiler_event.source, "body", "")
+
+            unspoiler = re.sub(r'<span[^>]+data-mx-spoiler[^>]*>(.*?)</?span>', r'\1', spoiler)
+            await self.send_fake_notice(room_id, unspoiler)
+
+
     async def send_reaction(
         self,
         room_id:   str,